Activists blocked the entrances to university buildings, occupied administrative offices, and marched in protest parades in cities including Berlin and Munich, as well as in university towns such as Heidelberg and Goettingen.

Around half of Germany's states allow universities to charge tuition fees, but most institutions do not and the system is chronically short of funding.

The marchers carried banners reading "Cough up the cash, rise up against social bandits", "Save education, not only the banks" and "Investment in education = guaranteed returns".

Organizers said 240,000 students took part while police estimated a number about half as high, local media said.

Marlene Gesche, a University of Potsdam student, was marching in Berlin because she said she felt cheated out of a decent education due to insufficient funding.

"I'm here protesting because I'm not really learning anything at my university", Gesche said. "There's no money for books. There is also often a lack of instructors".

A group of students chanted: "We're here and we're loud because our education is being stolen".

Margret Wintermantel, head of the German Rectors' Conference (HRK) of university presidents, said she could sympathize with some but not all of the reasons for the protests. "The student/teacher ratio is a problem", Wintermantel said.

But she rejected other demands of the protesters including abolishing tuition fees that some states have introduced and abandoning the European-standard bachelor and master degrees that are being phased in over several years.

"It's wrong to say that tuition fees limit equal opportunity for access to higher education", she said. "We haven't seen a decline in attendance where tuition fees have been introduced".

Some states now have fees of about 1,000 euros per year.

Germany's education minister, Annette Schavan, rejected most of the claims by the protesters, saying that on balance the German system had been improved in recent years. "Whoever says we have to do away with the bachelor and masters course of studies has not realized that Germany is part of a European-wide educational area", she told German radio.